🌅 Module 1 · Lesson 1/3

🔬How Small Is Small?

A zoom-in journey to the world where the everyday rules stop working.

⏱️ 12 minStart

🎯 By the end you will…

  • ✓Picture how tiny atoms really are
  • ✓Know what “quantum physics” studies
  • ✓Read powers of ten without fear

Everything you can touch — your hand, this screen, the air — is made of atoms. They are so small that a single grain of salt holds more than a billion billion of them.

Quantum physics is the rulebook for that tiny world: atoms, the electrons that surround them, and light itself. The surprising part? That rulebook is very different from the one we learn by throwing balls and riding bikes.

🎛️Interactive experiment

Drag the slider to zoom from your size down to an atomic nucleus. Each step shrinks the view 10 times.

🧮Equation, decoded

Powers of ten: the size of an atom

What each symbol means

  • Start at 1 and move the decimal point 10 places to the left: 0.0000000001
  • metres — about one big step
  • “roughly equal to” — physicists love good estimates

📖 Say it like a story

Line up ten billion atoms and you get one metre. A minus sign in the exponent simply means “divide by ten that many times”. That's all this notation is: a shortcut for counting zeros.

Three surprises waiting for you

1. Energy comes in packets. Tiny things can't have any energy — only certain amounts, like a staircase instead of a ramp.

2. Things are both waves and particles. An electron can spread out like a ripple, yet it always lands as a single dot.

3. Nature plays with probabilities. Quantum physics usually tells you the chances of each outcome, not the outcome itself.

✅ Check your understanding

Answer all questions to complete the lesson and earn XP.

  1. 1. What does quantum physics mainly describe?

  2. 2. How big is 10⁻³ metres?

  3. 3. Where is almost all of an atom's mass?

📚 Sources & further reading